The present invention relates to the use of .alpha.-acyloxy-N,N'-polyacylmalonamides as activators for mineral and organic percompounds, and more particularly, as activators for hydrogen peroxide, for its addition products with organic substances such as urea and dicyclohexylamine, and also of its mineral persalts such as perborates, percarbonates and perphosphates.
The action of aqueous solutions of percompounds as oxidizing and bleaching agents becomes effective only at temperatures above 70.degree. C. and preferably between 80.degree. and 100.degree. C.
The prior art describes numerous products exhibiting the property of acting as percompound activators, that is, permitting the achievement of a more rapid oxidizing or bleaching action than that which is customarily observed, or alternatively developing such action under much gentler temperature conditions than those which it is necessary to use in their absence, all these percompounds being characterized by the fact that they have one or more perhydrolyzable functions.
In the bleaching field, a certain number of activator compounds have begun to be developed commercially. The literature on this subject mentions especially poly-N-acetylated heterocycles of the hydantoin, glycoluril, benzimidazole and diketopiperazine type. However, this development has not been pursued because these substances display the major disadvantage of being unstable with reference to ambient humidity and of hydrolyzing spontaneously, thus rapidly losing their activator property.
Moreover, these products require special precautions for storage, handling or the addition of other ingredients, such as those used for instance in the usual washing powder compositions. Various solutions have been proposed to overcome this disadvantage: coating, separate packing, or addition of desiccating products, but these have not given satisfaction, either because they present technical problems in practical usage or because they lead to a considerable increase in the cost of the active substance.
There therefore exists an industrial need for available percompound activators which are stable for long periods in the solid state under normal conditions of storage and packing.